RESEARCH OBJECTIVES: The research of Epstein's laboratory is concerned with three aspects of the neuropsychology of ingestive behavior: 1) the physiological mechanisms of thirst, 2) the chemical controls of food intake, and 3) the ontogeny of ingestive behavior. Studies of the physiological mechanisms of thirst will emphasize the role of angiotensin in the mobilization of the thirst of extracellular depletions. The means by which it enters the brain and affects sensitive tissue will be sought and its interactions with the osmosensors for thirst that are focused in the lateral preoptic area will be studied. Two approaches will be taken to the study of the chemical controls of food intake. First, physiological doses of catecholamines will be used to analyze the possible adrenergic mechanism for the arousal and suppression of the brain mechanisms for meal taking. Second, glucose analogs and other antimetabolites of glycolysis will be used within the brain to better understand the means by which the brain mobilizes feeding in response to decreased intracellular glucose utilization (glucoprivation). The ontogeny of feeding and drinking will be studied in suckling and weanling rats with both appetitive and reflexive testing. The chronology of development of the separate physiological controls of each mode of ingestive behavior will be described and their assembly into adult feeding and drinking analyzed.